System and method for configuring a network element

ABSTRACT

A communication switch is provided for customer premise equipment. The switch comprises a communication module which processes communications between elements in the communication switch, a shelf module which has an interface point for the customer premise equipment to the communication module, and a chassis. The shelf module comprises an I/O card providing the interface point, a line processing card, a midplane providing a connections to the I/O card and the line processing card and connections for the midplane to the communication module. The shelf module communicates with the communication module via a communication link. The link may be connected and disconnected without disrupting operation of other shelf modules connected to said communication module.

FIELD OF THE INVENTION

[0001] The invention relates to a system and method of providing aflexible, modular architecture for a communication switch.

BACKGROUND OF INVENTION

[0002] In a communication switch, functionality is provided through aset of cards operating together to provide communication switching. Forthe cards, a midplane provides a physical connection means for a logicalgroup of cards. Cards are plugged into connections on the midplane. Themidplane provides common power, ground and data and control signals toeach card and may provide internal connections for specific signalsbetween cards.

[0003] While a convenient module is created by a populated midplane,there are disadvantages. For example, when a fault occurs on themidplane (e.g., an open or shorted circuit track or a faulty connector),the entire midplane must be replaced. Accordingly all componentspopulated on the midplane must be disabled, even components which areunaffected by the midplane fault, while the midplane is being replaced.

[0004] There is a need for a system and method providing switchingmodularity that improves upon the prior art systems.

SUMMARY OF INVENTION

[0005] In a first aspect, a communication switch connecting a customerpremise equipment to a communication network is provided. Thecommunication switch comprises a communication module adapted to processcommunications between elements in the communication switch, a shelfmodule providing an interface point for the customer premise equipmentto the communication module and a chassis comprising a mounting regionfor the shelf module. The shelf module comprises an input/output circuitcard providing the interface point, a line processing card providingdata processing of information transmitted between the customer premiseequipment and the communication switch, a midplane arrangement and asub-chassis housing the midplane arrangement, the line processing cardand the input/output card. The midplane arrangement provides a firstconnection arrangement adapted to connect the input/output card to themidplane, a second connection arrangement adapted to connect the lineprocessing card to the midplane, a third connection arrangement adaptedto provide at least one signal connection at least one of the firstconnection and second connection arrangements to at least one of theinput/output card and the line processing card, and a fourth connectionarrangement adapted to provide the midplane arrangement with at leastone signal connection for at least one of the first and secondconnection arrangements to the communication module. The shelf modulecommunicates with the communication module via a communication linkconnecting the third connection arrangement to the communication module.

[0006] The communication switch may have the other shelf modules housedin the mounting region of the chassis.

[0007] The communication switch may have the shelf and one of the othershelf modules as being redundant components to each other.

[0008] The communication switch may have the shelf module and the othershelf modules as being coincidentally supportable by a floor of themounting region.

[0009] The communication link may be connected and disconnected withoutdisrupting operation of other shelf modules connected to thecommunication module.

[0010] The communication switch may have the shelf module securable tothe chassis at a securing area at the top of the subchassis.

[0011] The communication switch may have the subchassis having an intakeair passage and an exhaust air passage for ventilation flow provided bythe communication switch.

[0012] The communication switch may have the intake air passage and theexhaust air passage individually selectively sealable from airflow uponan ambient temperature within the subchassis exceeds a safe threshold.

[0013] In a second aspect a modular shelf module for a communicationswitch for customer premise equipment is provided. The shelf modulecomprises an input/output circuit card providing the interface point, aline processing card providing data processing of informationtransmitted between the customer premise equipment and the communicationswitch, a midplane arrangement, and a chassis housing the midplanearrangement, the line processing card and the input/output card. Themidplane arrangement provides a first connection arrangement for theinput/output card to the midplane, a second connection arrangement forthe line processing card to the midplane, a third connection arrangementadapted to provide at least one signal connection of at least one of thefirst connection and second connection arrangements to at least one ofthe input/output card and the line processing card, and a fourthconnection arrangement for the midplane arrangement providing at leastone signal connection for at least one of the first and secondconnection arrangements to the communication module. The shelf modulecommunicates with a communication module in the communication switch viaa communication link connecting the third connection arrangement to thecommunication module.

[0014] The shelf module and the other shelf modules may be mountable ina mounting region of a chassis of the communication switch.

[0015] The shelf module and the other shelf modules may becoincidentally supportable by a floor of the mounting region.

[0016] The communication link may be connected and disconnnected withoutdisrupting operation of other shelf modules connected to thecommunication module.

[0017] The shelf module may be securable to the chassis at a securingarea at the top of the chassis.

[0018] The shelf module may have the chassis further comprising anintake air passage and an exhaust air passage for ventilation flowprovided by the communication switch.

[0019] The shelf module may have the intake air passage and the exhaustair passage as being individually selectively sealable from airflow uponan ambient temperature within the chassis exceeds a safe threshold.

[0020] In a third aspect, a network element for a communication networkis provided. The network element comprises a first set of circuit cardscomprising at least one circuit card arranged on one side of the networkelement, a second set of circuit cards comprising at least one circuitcard arranged on an opposite side of the network element, and a set ofmidplane cards. Each network element comprises at least one midplanecircuit card, with each of the midplane circuit cards adapted to connectat least one of the first set of circuit cards to at least one of thesecond set of circuit cards.

[0021] In a fourth aspect, a midplane arrangement for a network elementis provided. The midplane arrangement comprises circuit cards arrangedin a plane in a parallel spaced-apart arrangement on one side of theplane of midplane. These circuit cards define a first set of parallelplanes which perpendicularly intersect the plane of midplane. Themidplane arrangement also comprises a second set of circuit cards in aparallel spaced-apart arrangement on the other side of the plane ofmidplane. The second set of circuit cards define a second set ofparallel planes which perpendicularly intersect the plane of midplane.Each midplane circuit card is adapted to connect at least one circuitcard of the set of circuit cards to at least one circuit card of thesecond set of circuit cards.

[0022] In other aspects of the invention, various combinations andsubset of the above aspects are provided.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The foregoing and other aspects of the invention will become moreapparent from the following description of specific embodiments thereofand the accompanying drawings which illustrate, by way of example only,the principles of the invention. In the drawings, where like elementsfeature like reference numerals (and wherein individual elements bearunique alphabetical suffixes):

[0024]FIG. 1 is a block diagram of components of a switch embodying theinvention;

[0025]FIG. 2 is a block diagram of the switch, including a subshelfarrangement, of FIG. 1;

[0026]FIG. 3A is a front perspective view of the subshelf arrangementassociated with the switch of FIG. 2;

[0027]FIG. 3B is a front view of the subshelf arrangement associatedwith the switch of FIG. 2;

[0028]FIG. 3C is a side view of the subshelf arrangement associated withthe switch of FIG. 2;

[0029]FIG. 3D is a rear view of the subshelf arrangement associated withthe switch of FIG. 2;

[0030]FIG. 3E is a rear perspective view of the subshelf arrangementassociated with the switch of FIG. 2;

[0031]FIG. 3F is a partial end cut-away view of the subshelf arrangementassociated with the switch of FIG. 2;

[0032]FIG. 3G is a profile view of a midplane arrangement associatedwith the subshelf arrangement of FIGS. 3A-3F; and

[0033]FIG. 4 is a profile view of another subshelf arrangementassociated with the switch of FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The description which follows, and the embodiments describedtherein, are provided by way of illustration of an example, or examples,of particular embodiments of the principles of the present invention.These examples are provided for the purposes of explanation, and notlimitation, of those principles and of the invention. In the descriptionwhich follows, like parts are marked throughout the specification andthe drawings with the same respective reference numerals.

[0035] Referring to FIGS. 1 and 2, switch 100 is a multi-protocolbackbone system, which can process both of ATM cells IP traffic throughits same switching fabric. Switch 100 is connected to a communicationnetwork 101, allowing a customer premise equipment (CPE) 102 on one endof the network to communicate to a device at another end of the network.The CPE 102 may be a terminal, modem, computer or other device capableof communicating with another device. In the present embodiment, switch100 allows scaling of the switching fabric capacity from 50 Gbps to 450Gbps in increments of 14.4 Gbps simply by the insertion of additionalswitching shelves into switch 100.

[0036] It will be appreciated that terms such as “routing switch”,“communication switch”, “communication device”, “switch” and other termsknown in the art may be used to describe switch 100. Further, while theembodiment is described for switch 100, it will be appreciated that thesystem and method described herein may be adapted to any switchingsystem.

[0037] In switch 100, CPE 102 is connected via a link 104 to switch 100to I/O card 106. I/O card 106 provides the main interface for CPE 102 toswitch 100 for its datastream. Link 104 may be an optical, electrical orwireless link. But for converting the datastream into a format forswitch 100, I/O card 106 does not process the datastream. I/O card 106sends the datastream from CPE 102 to line card 108. Line card 108provides OC-192 functionality, ATM provisioning and ATM cell processingbetween core 110 of switch 100 and CPE 102. Each line card 108 is alsoconnected to a fabric interface card (FIC) 112 which converts thedatastream from the line card to an optical signal and sends thedatastream to core 110. In core 110, the datastream is routed to anappropriate egress path, leaves core 110 and is provided to an egresspath through an egress line card. For this example, the egress path maybe through line card 108B. A terminal (not shown) is connected torouting switch 100 and runs controlling software, which allows anoperator to modify, and control the operation of, switch 100. Theoverall operation and components of switch 100 are well known in theart, but for the embodiment described herein.

[0038] The line card 108, FIC 112 and I/O cards 106 are grouped on amidplane (described later) into a slot 114. Slots 114A, 114B, 114C and114D may be grouped into a High Speed Peripheral Shelf (HSPS),represented as peripheral shelf 116. As a shelf, HSPS 116 may beprovided with a redundant shelf 161B having a complementary set of slots114 and cards 106, 108 and 112 to HSPS 116. Alternatively other shelvesmay be provided in switch 100 having different functions, for exampleswitch control functions.

[0039] Shelf controller 118 is provided in switch 100 to arbitratecommands to each of the shelves 112.

[0040] Physically in the prior art, a shelf, like the HSPS 116, wasembodied in a single midplane, spanning the width of the cabinet ofswitch 100. However, the embodiment provides the improvement of aplurality of subshelves one of each for peripheral shelf 116 and asystem to allow cards on each subshelf to communicate with each other.In each subshelf 116, there is a midplane 120 which provides a physicalsubstrate onto which local cards may be mounted. Further detail on themidplane 120 is provided below.

[0041] Referring to FIG. 2, physically, switch 100 of the embodimentcomprises chassis 200 (shown in partial view) which has opening 202therein, providing a mounting region for the shelves 116. Within opening202, one of several subshelf modules, e.g., subshelf module 116A, may beinserted into one of four subslots 202A, 202B, 2024C or 202D of opening202. Fan units 204A, 204B and 204C, located in a compartment beneathopening 202, provide forced-air cooling to modules 116. Air intake isthrough the base of shelf 116A, i.e. below fans 204, in an opening. Airexhaust is through the rear top section of shelf 200. The openings aredescribed in detail later. Shelf controller circuits 118A and 118B arecommunication modules for switch 100 and provide centralized and modularcontrol systems for each of subshelves 116A . . . 116D via individualcommunication links (not shown). It will be appreciated that otherembodiments may have other communication modules providing centralizedand other switching or controlling functionality for switch 100. In theembodiment, each subshelf 116 is separately connected to at least one ofeach shelf controller 118. In a fully redundant configuration, eachsubshelf 116 is connected to both shelf controllers 118A and 118B. Theembodiment provides a connection arrangement allowing a subshelf to beconnected and disconnected individually to its target shelf controller118.

[0042] Referring to FIGS. 2 and 3A, 3B, 3C, 3D, 3E, 3F and 3G aspects ofsubshelf 116A are provided. Generally, subshelf 116A is a subchassis toswitch 200 and is an elongated rectangular form having sides 300, top302 and bottom 304. Referring to FIG. 3F, in the embodiment, subshelf116A is constructed of steel. The steel construction provides aFaraday-type shield from neighbouring electromagnetic sources. Furthershielding is provided by a gasket 330, which surrounds the edge ofsubshelf unit 116A along ridge 332.

[0043] At bottom 304 in opening 342, opening 342 is covered withhoneycomb material 346. Similarly, at top 302 in opening 344, opening344 is covered with honeycomb material 346. The honeycomb material 346normally allows air to flow through its cells, but disintegrates andseals its cells under high temperature conditions. Accordingly, whenthere is a fire or high heat condition inside subshelf 116A, the top andbottom honeycomb material 346 would seal themselves, thereby sealing theinterior of subshelf 116A from an exterior supply of oxygen.Accordingly, any internal fire or high heat condition in subshelf 116Awould be contained within itself and would be isolated from an externaloxygen supply.

[0044] In the embodiment, subshelf 116A has a width of approximately 120mm and a height of approximately 650 mm. The aspect ratio of height towidth of subshelf 116A requires that the stiffness of the sides 300 donot deflect under the gasket 330 load. Accordingly the front outer edgeof side 300 is a side having a generally flat surface on the interior300A and a shaped exterior 300B providing a generally first rectangularpocket at 334, followed by an indentation 332 for gasket 330 followed byanother pocket at 336. Accordingly, the profile of subshelf 116A is thatof an upright elongated box having a deep depth. It will be appreciatedthat other physical profiles may be used in other embodiments.

[0045] Again, referring to FIGS. 3A-3G, for airflow and cooling, on top302 of subshelf 116A, grid 318 provides a flow-through vent for air tocool components contained within subshelf 116A. Power for subshelf 16Ais provided externally. However, redundant power conditioning modules328A and 328B are provided to condition and regulate power signalsprovided to components in subshelf 116A.

[0046] Screw holes 338 located on top 302 in a flange 340 traversingfrom side 300 to opposite side 300. Screw hole 338 provides a securingarea for screws to secure subshelf 116A to a corresponding receptacle inchassis 102. Accordingly, the weight of subshelf 116A rests on the floorof by cavity 202, while the secured subshelf 116A is prevented fromlateral movement by the friction connection of the screw mounted throughholes 338 for subshelf 116A. This securement system provides a“swinging” securement system, which allows the subshelf 116A to be moreresilient under severe vibration conditions, e.g., during earthquakes.It will be appreciated that other securing systems may be used, such aspins, which provide the “swinging” connection properties, describedabove.

[0047] Accordingly, opening 204 may be populated with a plurality ofsubshelves 116 having similar dimensions or a mix of subshelves 116having different dimensions, in particular, different widths. Within thedimensions of a subshelf 116, it is further possible to develop custommidplanes for components specifically for that particular midplane.Accordingly, the embodiment provides greater flexibility in developinginterface mechanisms to communicate with shelf controller 118. Referringto FIG. 4, subshelf 400 is shown which is an exemplary double-widthshelf relative to subshelf 116 having a width of 240 mm and a height of640 mm. It will be appreciated that custom, double width cards may bepoulated therein.

[0048] Referring to FIG. 2 and FIGS. 3A-3G, midplane 120 has connectionsenabling line card 108, I/O card 106 and FIC cards 112 to communicatewith each other and with external elements, such as shelf controller118. Conductive tracks through midplane 120 connect selected pins inconnector 316A to selected pins in connector 316B. Further, connectors316A and 316B provide an link to shelf controllers 118 via appropriatecables (not shown). In the embodiment, subshelves 116 are connected tothe shelf controller 118 via optical control service links (CSLs) andare connected to the core 110 via high speed inter shelf links (HISLs).For EMI protection, a cage has been provided around connectors 316A and316B. The cage comprises a metal gasket 348 comprising metal stripswhich laterally surround the connectors 316 behind the exterior face ofsubshelf 116.

[0049] In subshelf 116A, a midplane assembly 120 spans between each side300 and from top 302 to bottom 304 and is fully contained withinsubshelf 116A. The midplane 306 has front area 308 and back area 310,separating the subshelf 116A into a front and rear portion. On frontarea 308, connectors 312 are provided to allow cards to be inserted intothe front portion of subshelf 116. On the rear 310, connectors 314 areprovided to allow other cards to be connected to the rear of midplane120. In the rear section of subshelf 116A, cross members 320 spanbetween sides 300 and segment the rear portion of subshelf 116A into aplurality of vertical subunits 322. Each cross member 320 may be securedto midplane 120 via screw 322 through aperture 324 in cross member 320.Each cross member 320 has slots 326 to guide cards as they are beinginserted into their respective connectors 314. It will be appreciatedthat the connectors and the cross members 320 may be configured indifferent embodiments to have different size region(s) therein.

[0050] In the embodiment line card 108 may be inserted into the front ofsubshelf 106 and connect to midplane 306 via connectors 312. Similarly,I/O cards 106 may connect to connectors 314 to provide a connectionbetween line cards 108 and I/O cards 106.

[0051] It will be appreciated that having a several smaller midplanes insubshelves 116 in a switch 100 provides a less expensive circuitboardfor each midplane as opposed to a single, larger midplane. It will beappreciated that collectively, the subshelves provide an architecturewhere individual shelves provide modular redundant components or modularcomplementary components for switch 100. It is notable that a switchutilizing a prior art single midplane architecture which would span theentire back of cavity 202 has the disadvantage that any failure in themidplane would require the disconnection of all components connectedthereto, even components not affected by the failure in the midplane, inorder to replace and correct the error in the midplane.

[0052] The features and advantages of this embodiment are as follows:

[0053] 1) reliability and serviceability is improved for the routingswitch;

[0054] 2) network redundancy is provided mechanically within a shelf;

[0055] 3) design of shelf midplane is simplified; and

[0056] 4) expansion and upgrading of a sub-shelf for a midplane can beaccomplished without affecting the rest of the shelf.

[0057] It is noted that those skilled in the art will appreciate thatvarious modifications of detail may be made to the present embodiment,all of which would come within the scope of the invention.

We claim:
 1. A communication switch connecting customer premise equipment to a communication network, said communication switch comprising: a communication module adapted to process communications between elements in said communication switch; a shelf module providing an interface point for said customer premise equipment to said communication module, said shelf module comprising an input/output circuit card providing said interface point; a line processing card providing data processing of information transmitted between said customer premise equipment and said communication switch; a midplane arrangement providing a first connection arrangement adapted to connect said input/output card to said midplane, a second connection arrangement adapted to connect said line processing card to said midplane, a third connection arrangement adapted to provide at least one signal connection from at least one of said first connection and second connection arrangements to at least one of said input/output and said line processing cards; and a fourth connection arrangement adapted to provide said midplane arrangement with at least one signal connection for at least one of said first and second connection arrangements to said communication module; a sub-chassis housing said midplane arrangement, said line processing card and said input/output card; and a chassis comprising a mounting region for said shelf module, wherein said shelf module communicates with said communication module via a communication link connecting said third connection arrangement to said communication module.
 2. A communication switch as claimed in claim 1 wherein said other shelf modules may be housed in said mounting region of said chassis.
 3. A communication switch as claimed in claim 2 wherein said shelf and one of said other shelf modules are redundant components to each other.
 4. A communication switch as claimed in claim 3 wherein said shelf module and said other shelf modules are coincidentally supportable by a floor of said mounting region.
 5. A communication switch as claimed in claim 4 wherein said shelf module is securable to said chassis at a securing area at the top of said subchassis.
 6. A communication switch as claimed in claim 5 wherein said communication link may be connected and disconnected without disrupting operation of other shelf modules connected to said communication module.
 7. A communication switch as claimed in claim 6 wherein said subchassis provides an intake air passage and an exhaust air passage for cooling ventilation provided by said communication switch.
 8. A communication switch as claimed in claim 7 wherein said intake air passage and said exhaust air passage are individually selectively sealable from airflow upon an ambient temperature within said subchassis exceeds a safe threshold.
 9. A modular shelf module for a communication switch, said shelf module connecting a customer premise equipment to said communication switch, said shelf module comprising: an input/output circuit card providing said interface point; a line processing card providing data processing of information transmitted between said customer premise equipment and said communication switch; a midplane arrangement comprising a first connection arrangement adapted to provide a connection for said input/output card to said midplane arrangement, a second connection arrangement adapted to provide a connection for said line processing card to said midplane, a third connection arrangement adapted to provide at least one signal connection from at least one of said first connection and second connection arrangements to at least one of said input/output and said line processing cards; and a fourth connection arrangement adapted to provide said midplane arrangement with at least one signal connection for at least one of said first and second connection arrangements to said communication module; a chassis housing said midplane arrangement, said line processing card and said input/output card; wherein said shelf module communicates with a communication module in said communication switch via a communication link connecting said third connection arrangement to said communication module.
 10. A shelf module as claimed in claim 9 wherein said shelf module and said other shelf modules are mountable in a mounting region of a chassis of said communication switch.
 11. A shelf module as claimed in claim 10 wherein said shelf module and said other shelf modules are coincidentally supportable by a floor of said mounting region.
 12. A shelf module as claimed in claim 11 wherein said shelf module is securable to said chassis at a securing area at the top of said chassis.
 13. A shelf module as claimed in claim 12 wherein said chassis further comprises an intake air passage and an exhaust air passage for cooling ventilation provided by said communication switch.
 14. A shelf module as claimed in claim 13, wherein said communication link may be connected and disconnnected without disrupting operation of other shelf modules connected to said communication module.
 15. A shelf module as claimed in claim 14 wherein said intake air passage and said exhaust air passage are individually selectively sealable from airflow upon an ambient temperature within said chassis exceeds a safe threshold.
 16. A network element for a communication network, comprising: a first set of circuit cards comprising at least one circuit card arranged on one side of the network element; a second set of circuit cards comprising at least one circuit card arranged on an opposite side of the network element; and a set of midplane cards comprising at least one midplane circuit card, each of said midplane circuit cards adapted to connect at least one of said first set of circuit cards to at least one of said second set of circuit cards.
 17. A midplane arrangement for a network element, comprising: a plurality of circuit cards arranged in a plane; a first plurality of circuit cards in a parallel spaced-apart arrangement on one side of the plane of midplane circuit cards and defining a first set of parallel planes which perpendicularly intersect the plane of midplane circuit cards; and a second plurality of circuit cards in a parallel spaced-apart arrangement on the other side of the plane of midplane circuit cards and defining a second set of parallel planes which perpendicularly intersect the plane of midplane circuit cards; wherein each midplane circuit card is adapted to connect at least one circuit card of the first plurality of circuit cards to at least one circuit card of the second plurality of circuit cards. 